Patsula O.I. Adaptation reactions of sunflower plants to toxic influence of lead and cadmium ions. – Manuscript.
Thesis for a Ph.D degree on biological sciences by speciality 03.00.12 – plant physiology. – 2005.
The dissertation is devoted to investigation of adaptive reactions of sunflower plants to toxic influence of lead and cadmium ions. It was shown that growth of the sunflower plants on the lead acetate and cadmium chloride solutions increases their ability to accumulate these metals in their roots. Cadmium ions were accumulating more then lead ions.
Determination of the tolerance index indicated increasing of this exponent under conditions of the transferring plants from variants with lower concentration of heavy metals to the solutions with higher concentration. The incoming of heavy metals into plants results in accumulation of hydrogen peroxide. Especially, contents of hydrogen peroxide were increasing under condition of transferring plants from solutions with lower concentration of heavy metals to solutions with highest concentrations of these metals, that indicates it’s involvement in the processes of activation of the antioxidative system.
Increased concentration of lead ions in the solutions due to increasing activity of catalase. Also in the 14-day old sunflower plants was shown decreasing of catalase and peroxidase activity on lead solutions. Is established that cadmium ions simulat********************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************of their action. Lead effects were results in reduction of glutathione reductase activity in the 7-day old plants and increasing it activity in the 14-day old sunflower plants. Cadmium ions, under effect of lower concentrations, due to activation of glutathione reductase. Positive result is indicated under conditions of transferring plants from the lower concentration of cadmium chloride to higher.
Altogether is indicated that transferring plants from solutions with lower concentrations of heavy metals on the solutions with highest concentration proceeds in the accumulation of the heavy metals by plants, increasing tolerance index, hydrogen peroxide and glutathione content. On early stages of the heavy metals effect efficiently operates glutathione reductase, at subsequent growth – catalase and peroxidase.
Key words: adaptation, lead, cadmium, reduced glutathione, catalase, peroxidase, glutathione reductase.
| 
